Roof ventilator

ABSTRACT

A device for ventilating and relieving moisture from the underlying insulating layer of a sealed roof comprises a flat plastic base having a central opening which is surrounded by an upstanding integrally molded hollow plastic stack which has an opening at its top. The top of the stack has notches for receiving tight-fitting webs which project integrally from the concave bottom of a molded cap. The webs space the cap from the stack so as to provide a flow path for relieving entrapped moisture from the roofing insulation. In order

l United States Patent 1151 3,685,426 Rosa 1 1 Aug. 22, 1972 1 ROOF VENTILATOR Prima Examiner-Me er Perlin 72 1 t Dani 1 Y 1 men or Wis e F Rosa Menomonee Falls Assistant Examiner-Ronald C. Capossela Attorney-Wiviott and Hohenfeldt [73] Assignee: Medi-Pla Sciences, Inc. 22 Filed: Oct.9, 1970 [57] ABSTRACT A device for ventilating and relieving moisture from [21] Appl' 79535 the underlying insulating layer of a sealed roof comprises a flat plastic base having a central opening [52] US. Cl. ..98/83, 52/200, 98/66 whi h is surrounded by an upstanding integrally 51 1111.01 ..F23l 17/02 melded hollow plastic sleek which has an Opening at [58] Field of Search ..98/35, 37, 42, 42.1, 66, 83, its p- The p of the Stack has notches for receiving g g 225x 99 20 tight-fitting webs which project integrally from the concave bottom of a molded cap. The webs space the [56] References Cited cap from the stack so as to provide a flow path for relieving entrapped moisture from the roofing insula- UNITED STATES PATENTS tion.

In order to relieve moseDe, vents are installed at 3: spaced intervals overD)hdDDoEv irea. These vents i are essentially hollow stackes which are set over 3,112,687 12/1963 Henneberger ..98/37 3,521,414 7/1970 Malissa ..52/200 X 3 Clains, 4 Drawing Figures PATENTEDMIBZZ I912 3.685426 INVENTOR,

FIG.4

DANIEL F. ROSA 22 4 23 I Attorney BACKGROUND OF THE INVENTION Buildings which have roofs built up of asphalt or tar and gravel are inclined to trap moisture in the porous insulating material which usually underlies the roof. This moisture may get into the insulation by means of leaks in the roof or as a result of it being condensed from the humid air inside of the building. Moisture degrades the insulating properties of the insulating material under the roof and it also causes metal structural parts to rust.

In order to relieve moisture, vents are installed at spaced intervals over the roof area. These vents are essentially hollow stacks which are set over a recess which has been cut in the roofing material so as to expose the underlying insulating layer. Moisture thereby has an opportunity to evaporate and emerge from the stack. Capillarity and convection constantly conduct moisture to the relatively dry area under the stack so that the whole insulating layer under the roof will eventually dry up.

Prior art vents usually have metal caps which are exposed to the cold outside air and condense moisture. When the air is cold enough, this condensation freezes. As the ambient temperatures rises, the ice forms droplets which fall back onto the insulation and wet it and defeat the purpose of the vent to some extent.

Another problem with prior art roofing vents is that they require much labor to install in a leakproof manner. This is so because it is necessary to build up the roofing material or some other sealing layer along the sides of the stack in order to make a leakproof joint between the vent and the existing roofing material.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the foregoing problems by providing a roofing vent which has no exposed metallic parts and is inherently insulating, strong, lightweight, unitary and easy to install.

A further object of the invention is to make a roofing vent out of plastic such as urethane foam which has a hard, smooth and impervious surface or skin that makes it easy to paint and imparts self-cleaning properties to it.

Briefly stated, the new roof vent comprises a molded perforated base on which there is an upstanding hollow truncated cone constituting a stack member. A molded cap member fits on the top of stack in such manner thatan air flow space is provided through which moistureladen air may be liberated. The cap has a concave bottom on which there are circumferentially spaced webs that engage notches in the top of the stack so as to fix the cap centrally on the stack.

Achievement of the foregoing objects and other more specific objects of the invention will appear from time to time throughout the course of the ensuing detailed description of the invention taken in conjunction with the drawing.

DESCRIPTION OF THE DRAWING FIG. 1 shows an elevation view of the new vent installed in a roof;

FIG. 2 is a perspective view of the integral base and stack of the vent with the cap removed;

FIG. 3 is a top view of the cap isolated from the stack; and

FIG. 4 is a vertical cross section of the cap taken on a line corresponding with 4-4 of FIG. 3.

DESCRIPTION OF A PREF EMBODIMENT v FIG. 1 illustrates the general construction of the new vent and shows one installed in a roof. The vent comprises a substantially planar but slightly beveled base 10 which has a central opening 11. Integrally molded with base 10 is an upstanding hollow truncated cone constituting a stack 12 which has a central opening 13 at its top. On top of stack 12 is a cap 14 which overhangs the stack and is supported on the stack in such a manner that there is a free space 15 from which moisture entrapped underneath a roof may emerge.

In the illustrative installation of the vent device shown in FIG. 1, the base 10 rests on the subsisting insulating layer 16 underlying the roof. A portion of the roof may be prepared for setting base 10 of the vent by removing a section of the top layer of the roofing material 17. The top roofing layer 17 is removed to allow base 10 to rest on underlying insulation 16. Prior to placing the vent, it is desirable to remove part of insulating layer 16 and replace it with rock wall or other porous material 19 in the region under bottom opening 1 l of stack 12. The porous piece 19 augments evaporation of moisture up the stack.

Structural details of the new vent and the method and materials for making it will now be discussed in reference to FIGURES 2-4. The parts shown in these figures are preferably made of molded polyurethane foam. The molding process is such that a skin surface is formed on the parts which makes them smooth and easy to paint. The polyurethane foam material is distinguished by its ability to withstand heat, cold and corrosive atmosphere. Its appearance can be maintained with almost any type of paint or coating. Its life can be expected to exceed the normal 15 to 20 year life expectancy of a fabricated roof.

In FIG. 2 one may see that the truncated cone which forms stack 12 has its top edges provided with three equi-angularly spaced notches 20. The fiat bottoms of these notches constitute a bearing surface for a horizontal shoulder 21 on the three equi-angularly spaced webs 22 which project radially inwardly on the underside of cap 13. The webs 22 also have a depending margin 23, see FIG. 4, which extends partially down the outside of cone 12 when the flat shoulder 21 is bearing on the bottom of notch 20. Thus, when all the webs 22 are registered in notches 20, cap 13 is properly centered and prevented from lateral shifting. The webs or an equivalent could be on the top edge of the conical stack and the notches or their equivalent could be on the cap. The notches may be eliminated if desired.

Whether or not the notches are present, cap 14 may be secured on stack 12 merely by driving one or more nails in the side of the cap through webs and into the wall of the stack. An alternate method of securing the cap on the stack is to apply adhesive in the notches before webs 22 are registered therein or to apply it to the webs if there are no notches. It should also be noted that base 10 may be nailed down easily where the substrate permits because the base is made of polyurethane. In any case, the laterally extending integrally flat molded base l improves the stability of the vent and makes its installation easier. This contrasts with prior vents which hadsome molded parts but which had no flange type base and thereby presented some appropriate recess has been formed in the existing roofing material as described earlier, the vent may be merelyset in place and the recess surrounding it may be poured full of any suitable roofing sealant to create a permanent installation. The insulating nature of the exposed plastic cap 14 and conical stack 12 is such that condensate will not form on the inside of the vent so as to partially defeat its intended purpose as was the case r with prior art vents.v

"Although a preferred embodiment of the new roof vent has been described in considerable detail, such description is intended to be illustrative rather than limiting, for-the invention may be variously embodied and is to be limited only by interpretation of the claims which follow:

a I claim:

l. A roof ventilator comprising:

a. a stack member comprised of rigid foamed polyurethane, said stack member being a hollow cone having an open upper endwhich isof smaller diameter than its open base end and said upper end having axially open notches,

b. a substantially planar base. means integrally molded with the lower end of the stack member and being of the same material as the stack.

member, said base means having an opening thatis aligned with said stack member,

. a cap means comprised of rigid polyurethane foam and adapted to be located on the upper open end of said stack member and to overhang said member, the underside of said cap means having integrally molded spaced apart web means, the web means being sized to fit into said notches to support said cap means with anair. flow space between it and said stack member.

. The invention set forth in claim 1 wherein: the said web means are generally disposed in the axial direction of the cap means and are provided with radially disposed shoulders that respectively bear on the bottom of the notches to support the cap means.

. The invention set forth in claim 2 wherein: said web means have a depending portion contiguous with said shoulder, said depending portions effecting symmetrical spacing of the cap means on the stack member. 

1. A roof ventilator comprising: a. a stack member comprised of rigid foamed polyurethane, said stack member being a hollow cone having an open upper end which is of smaller diameter than its open base end and said upper end having axially open notches, b. a substantially planar base means integrally molded with the lower end of the stack member and being of the same material as the stack member, said base means having an opening that is aligned with said stack member, c. a cap means comprised of rigid polyurethane foam and adapted to be located on the upper open end of said stack member and to overhang said member, the underside of said cap means having integrally molded spaced apart web means, the web means being sized to fit into said notches to support said cap means with an air flow space between it and said stack member.
 2. The invention set forth in claim 1 wherein: a. the said web means are generally disposed in the axial direction of the cap means and are provided with radially disposed shoulders that respectively bear on the bottom of the notches to support the cap means.
 3. The invention set forth in claim 2 wherein: a. said web means have a depending portion contiguous with said shoulder, said depending portions effecting symmetrical spacing of the cap means on the stack member. 